Johnson, UK, Ninety discussed on TIME's Top Stories
Has three safe and effective covid nineteen vaccines being shipped around the country and making it into people's arms all meet the us food and drug administration's threshold for protecting people from cova nineteen disease yet. Two of them are about ninety. Five percent efficacious while another is sixty six percent efficacious. Which may make tempting to rank them and assume that people receiving the sixty six percent efficacious shot are somehow less protected against covid nineteen. That's not the case however since it's not really possible to compare the vaccines to each other to start. There's a difference between efficacy and effectiveness. Efficacy refers to the results for how well a drug or vaccine works based on testing while effectiveness refers to how well these products work in the real world and a much larger of people most people however use them interchangeably. Next it's important to understand what these companies were actually measuring to come up with their efficacy numbers and the case of the covid nineteen vaccines. The researchers were measuring. How well they're vaccines protected against symptoms of covid nineteen. So they're vaccine efficacy numbers referred to how well they lowered people's chance of getting sick with covid nineteen pfizer by owen. Tech's vaccine is ninety. Five percent efficacious meaning that four vaccinated people it was ninety five percent efficacious and protecting people from getting covid nineteen symptoms. It does not mean that ninety five percent of people vaccinated won't get covid nineteen and five percent will similarly maderna's vaccine is ninety four percent efficacious. So it was ninety four percent efficacious in protecting people from covid nineteen and johnson. And johnson's vaccine is sixty six percent efficacious in doing the same. But that doesn't tell the whole story for a few reasons. First the vaccines work in different ways. Visor bio intech and madonna developed their vaccines using 'em in a technology which involves taking the genetic code for the spike protein of the sars covy to virus and encasing it in a fat based particle that is injected into the body once inside sales those viral genes instruct immune cells to produce copies of the protein which in turn switches the immune system. Interaction churning out sells like antibodies among other activities if the vaccinated person then gets infected with the actual virus. The body is ready to quickly. Produce those same antibodies that can stick to the virus and block it from infecting cells. Johnson and johnson janssen's vaccine uses a different strategy a weakened cold virus that has reprograms to include the code for the spike protein. Once inside the body the viral genes trigger a similar dedicated response against the virus because vaccines use different ways. To alert the immune system. The differing technologies could lead to varying degrees of efficacy second each vaccine has different dosing. Regimens visor bio intex and modernise shots require two doses in pfizer bio intex case. The two shots are one days apart. And in maderna's case they are twenty eight days apart. Janssen's vaccine is a single shot. Pfizer bio intech and madonna say. Their shots can stimulate the immune system after a single dose. But the second dose is needed to trigger the maximum response. Janssen's scientists are also testing a booster dose of their vaccine to see if it to might amplify the immune response third the vaccine companies started recording covid nineteen symptoms at different times after vaccination to see how well their shots could prevent disease and their respective late stage studies visor bio intech started recording symptoms seven days after people received the second shot of its vaccine or placebo. Madonna started fourteen days after the second dose and jansen recorded results from both fourteen days in twenty eight days after it single dose for the vaccines were tested at different times. that's important because of the genetic variants of the virus some of which are more infectious than the original that have emerged in recent months after some companies had already completed initial testing of their vaccines visor bio intech and modern up. Both tested their shots through most of twenty twenty. When sars cov two had not mutated as much so most of the study participants who are infected. Were infected by the same viral strain. Johnson however started its large phase three trial in september and included people in the uk south africa and brazil the three countries where new mutated variants of the virus started to spread quickly. Indeed many of the people in janssen's trial in those countries were infected with the new variants from a scientific point of view that means janssen study provided important clues about how well its vaccine could confront the growing threat of new variants of the virus. That could also explain why the janssen vaccine's efficacy is lower than those of the pfizer bio intech and maternal shots. In fact studies have since shown that among people vaccinated with pfizer biontech and moderna vaccines level of antibodies against the south african. Variant in particular are up to sixfold lower compared to levels against the non mutated virus. So for all of these reasons comparing the three vaccines is a bit like comparing apples to oranges. What's important is that all fight covid. Nineteen according to the fda's standard of efficacy. Which is that vaccines should be. At least fifty percent efficacious and protecting people from disease and all are extremely effective in protecting people from getting severely ill willed or dying from nineteen which ultimately is what we'd won't any vaccine to do..